At coffee shops, the icy brew is usually stored in a keg, pressurized, and poured from a tap:

The result is a foam finish, and those little champagne-like bubbles rising to the top.

Also worth noting? This stuff is strong.

Laura Metzler / for BuzzFeed

Or at the very least, the caffeine rush can hit you faster. With some brews, that's because of an amped up coffee-to-water ratio, said Josh Brodey, coffee manager at Slipstream in Washington, DC. (Another theory? That the nitrogen might lead to faster absorption rates.)

Packaged versions are also popping up in some markets.

In Austin and Houston, you can find ones from Cuvee Coffee and District Roasters. Stumptown is testing a canned version in Oregon and California, in addition to serving it on tap at its locations in Portland, Seattle, Los Angeles, and NYC. “Shipments are selling out every week,” said Aylsworth. “This year feels like the tipping point."

But for coffee aficionados who can't find the stuff locally — or for those not buying the hype — Brodey suggests a similar DIY alternative, sans the fancy nitrogen.

"If you have a pour-over coffee maker, brew the same amount of coffee that you usually do," said Brodey. "But use 2/3 of the water that you usually do, and replace that last 1/3 with ice. You'll have what's basically a flash pour-over, or a Japanese iced coffee."

You won't get the slightly bubbly feel, but you'll get a crisp, concentrated cup — in less time than other iced coffee methods.